Paper feeder enabling proper feeding alignment

ABSTRACT

A paper feeder including a pickup roller, a separation roller, a separation pad, a pressing device, and a separation plate is provided. The separation roller is located downstream the pickup roller. The separation pad leaning on the separation roller has a curved separation portion. The pressing device has a spherical node. The separation plate has a cavity on a back thereof for allocating the spherical node, and it also has a V-shaped slit on a front thereof for pressing the separation pad on the separation roller. As the spherical node is pressed on the separation pad, the V-shaped slit is guided to parallel to the shaft of the separation roller so as to have the separation pad precisely assembled on the surface of the separation roller.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to a paper feeder, and more particularly relates to a paper feeder enabling proper feeding alignment.

(2) Description of the Prior Art

Scanner were unusual peripheral products for early computer usage. For its complex operating procedure, scanners were mainly used by professional digital image operating users. However, attending with the progressing of digital image technology, cheap and user friendly scanners are available in the market and have become indispensable for personal users or small size offices.

Scanners at present are classified into feeder type and flatbed type briefly. The flatbed type scanner has a design similar to a small-sized copier, which is characterized by placing paper, books, or other documents to be scanned on a glass plate. Due to the advantages of small size and low cost, flatbed type scanner is more popular among those who are self-employeed. Nowadays, with the progress of scanning technologies, scanning of three-dimensional objects has become feasible for flatbed-type scanners.

In contrast with the flatbed-type scanners, feeder-type scanners are mainly used for the demand of large amount documents situation. A major advantage of feeder-type scanners is the so-called multi-page continuously scanning function, which leads to a relatively high scanning speed. However, due to the multi-page scanning design, feeder-type scanners cannot scan stapled documents, photographs, or three-dimensional objects.

FIG. 1 shows a paper feeder 10 of a typical automatic document feeder (ADF), which includes a pickup roller 12, a pickup arm 14, a separation roller 16, and a separation pad 18. The pickup arm 14 is pivotally connected to a shaft 16 a of the separation roller 16. The pickup roller 12 is assembled to a movable end of the pickup arm 14. The separation pad 18 is fixed in the paper feeder 10. The separation pad 18 can be divided into a feeding portion 18 b and a separation portion 18 a. There is a gap between the separation portion 18 a and the separation roller 16 with the dimension ranged between the thickness of one sheet of paper and two sheets of paper.

As sheets of paper S is fed, the movable end of the pickup arm 14 lowers along direction Y so as to have the pickup roller 12 attaching the sheets of paper S. The sheets of paper S are then driven by the pickup roller 12 along direction Z. The sheets of paper S are blocked by the separation pad 18 and the separation roller 16, and only the uppermost sheet of sheets of paper S can penetrate the gap between the separation portion 18 a of the separation pad 18 and the separation roller 16 into the ADF.

It is understood that the shape and assembling procedure of the separation pad 18 has great influences toward the paper separating ability of the paper feeder 10. For example, as the procedure of assembling separation pad 18 on the separation roller 16 has some mistake to form an error between the direction of the shaft 16 a and the rear edge (the left edge of the separation portion 18 a) of the separation portion 18 a, since the front edge of the sheets of paper S is directed by the rear edge of the separation portion 18 a before it is loaded into the ADF, the error may result in the problem of misalignment.

In addition, due to the fixed separation pad 18, the gap between the separation portion 18 a and the separation roller 16 is restricted. Thus, as the thickness of one sheet of the sheets of paper S varies, the problems of feeding trouble or multiple feed may happen.

Accordingly, it has become an important issue in the development of paper feeder to prevent the problems of feeding misalignment and multiple feed.

SUMMARY OF THE INVENTION

It is a main object of the present invention to have separation pad precisely positioned and assembled on the separation roller to prevent the problem of feeding misalignment.

It is another object of the present invention to have the gap between the separation pad and the separation roller adjustable to prevent multiple feed.

A paper feeder including a pickup roller, a separation roller, a separation pad, a pressing device, and a separation plate is provided. The pickup roller is utilized for driving sheets of paper. The separation roller is located downstream the pickup roller. The separating pad leaning on the separation roller has a curved separation portion. The pressing device has a spherical node. The separation plate has a cavity on a back thereof for allocating the spherical node, and has a V-shaped slit on a front thereof for pressing the separation pad on the separation roller. As the spherical node is pressed on the separation plate, the V-shaped slit is guided to be parallel to the shaft of the separation roller so as to have the curved separation portion of the separation pad precisely leaning on the surface of the separation roller.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which:

FIG. 1 shows a schematic view of a paper feeder within a typical automatic document feeder (ADF);

FIG. 2 shows a cross-section view of a preferred embodiment of the ADF in accordance with the present invention;

FIG. 3A shows an enlarged cross-section view of the paper feeder in FIG. 2;

FIG. 3B shows an enlarged cross-section view of the separation plate in FIG. 2;

FIG. 3C is an explosive view of the paper feeder in FIG. 2;

FIG. 4 shows a schematic view of a second preferred embodiment of the paper feeder in accordance with the present invention; and

FIG. 5 shows a schematic view of a third preferred embodiment of the paper feeder in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 shows a cross-section view of a preferred embodiment of an automatic document feeder (ADF) 20 in accordance with the present invention. As shown, the ADF 20 has a paper tray 30, a paper feeder 40, a midway roller set 50, and an exit roller set 70. The paper tray 30 is utilized for placing papers (not shown). The paper feeder 40 is utilized for driving the papers on the paper tray 30 to load into the ADF 20 one by one. The midway roller set 50 is located downstream the paper feeder 40 and is utilized for taking the paper away from the paper feeder 40 to a scanning or printing position 60 to be scanned or copied. The exit roller set 70 is located downstream the midway roller set 50 and is utilized for taking the sheet of paper away from the scanning or printing position 60 and for outputting the sheet of paper from the ADF 20.

FIG. 3A shows an enlarged view of the paper feeder 40 of FIG. 2. As shown, the paper feeder 40 has a pickup roller 42, a separation roller 44, a separation pad 45, a pressing device 47, and a separation plate 46. The pickup roller 42 is located near a rear end of the paper tray 30 for driving the sheet of paper on the paper tray 30 toward the separation roller 44, which is located downstream the pickup roller 42. The separation pad 45 has a curved portion 452 leaning on the surface of the separation roller 44. It is noticed that the paper driven by the pickup roller 42 are blocked by the separation roller 44 and the separation pad 45, and only the uppermost sheet of paper driven by the separation roller 44 penetrates the gap between the separation roller 44 and the separation pad 45 to be loaded into the ADF.

Referring to FIG. 3C, the pressing device 47 of FIG. 2 has a spherical node 472, a basis 474, and an elastic unit 476. The basis 474 has an opening 475 to have the spherical node 472 protruding downward in contact with the separation plate 46 underneath. The elastic unit 476 is located above the spherical node 472 to generate forces having the spherical node 472 pressing on the separation plate 46. Although the elastic unit 476 as shown is a compression spring in the present embodiment, it should not be a limitation and any sort of elastic unit 476 with the ability of being deformed to generate forces to the spherical node can be applied in the present invention.

Referring to FIG. 3B, in order to have the spherical node 472 pressing on the separation plate 46 effectively, the separation plate 46 has a cavity 462 on a back (the lower surface as shown) for allocating the spherical node 472. In addition, the cavity 462 of the separation plate 46 shows a curved surface with the curvature smaller than the spherical node 472 to guarantee the spherical node 472 touching the bottommost of the cavity 462 to have the spherical node 472 pressing on the separation plate 46 precisely and effectively. As a preferred embodiment, the cavity may have a spherical surface 462 just fitting the shape of the spherical node 472.

In addition, as shown in FIG. 3B, the separation plate 46 has a V-shaped slit 464 on a front (the upper surface as shown) for pressing the separation pad 45 on the separation roller 44. The separation plate 46 is movably assembled on the basis 474 of the pressing device 47, and the separation pad 45 is movably assembled on the separation plate 46. As the spherical node 472 is pressed on the separation plate 46, the V-shaped slit 464 on the separation plate 46 is guided by the separation roller 44 to be parallel to the shaft of the separation roller 44. At the same time, the separation pad 45 is guided by the V-shaped slit 464 to have a rear edge 45 a of the separation portion 452 thereof parallel to the shaft of the separation roller 44 so as to have the curved separation pad 45 precisely leaning to the separation roller 44.

Moreover, the pressing device 47 as shown has a gap adjusting screw 477 and a force adjusting screw 478. The gap adjusting screw 477 is screwed fixed to the basis 474 and contacts the rear end of the spherical node 472 for adjusting the length of the spherical node 472 protruding from the basis 474 to determine the gap between the separation pad 45 and the separation roller 44. In addition, the gap adjusting screw 477 also fixes the separation plate 46 on the basis 474.

The gap adjusting screw 477 has a screw hole 479. The elastic unit 476 is located in the screw hole 479 and contacts the spherical node 472 above. The force adjusting screw 478 is screwed fixed in the lower portion of the screw hole 479 and contacts the elastic unit 476 above. Therefore, by changing the depth the force adjusting screw 478 screwed into the screw hole 479, the deformation of the elastic unit 476 can be adjusted to calibrate the force applied by the spherical node 472 to the separation plate 46.

In addition, a calibration pad (not shown) adapted for adjusting the size of the gap between the separation pad 45 and the separation roller 44 is provided in the present invention. The calibration pad is set to have a thickness ranged between one sheet of paper and two sheets of paper. By using calibration pads with various thickness, the ADF in the present invention can prevent the problem of feeding trouble and multiple feed when paper with various thicknesses are applied. In the adjusting procedure, the calibration pad is firstly interposed into the gap between the separation pad 45 and the separation roller 44. Then, the gap adjusting screw 477 is rotated to have the separation pad 45 pressing on the calibration pad on the separation roller 44. The depth the gap adjusting screw 477 screwed into the basis 474 represents the size of the gap between the separation pad 45 and the separation roller 44, which is determined by the calibration pad.

FIG. 4 shows a second preferred embodiment of the paper feeder in accordance with the present invention. In compared with the first embodiment shown in FIG. 3A, the gap adjusting screw 477′ in the second embodiment specifies with a hole 479′ having a closed lower end and the force adjusting screw 478 is omitted. However, since the force adjusting screw 478 is omitted in the present embodiment, the depth of the hole 479′ should be calibrated to determine the force applied by the elastic unit 476 to the spherical node 472.

FIG. 5 shows a third preferred embodiment of the paper feeder in accordance with the present invention. In compared with the first embodiment shown in FIG. 3A, the present embodiment has a hole formed on the basis 474′ for allocating the elastic unit 476. In addition, the gap adjusting screw 477 and the force adjusting screw 478 are omitted in the present embodiment. However, since the gap adjusting screw 477 and the force adjusting screw 478 are omitted, the depth of the hole on the basis 474′ should be calibrated to adjust the size of the gap between the separation pad 45 and the separation roller 44, and a suitable force applied by the elastic unit 476 to the spherical node 472 should be determined.

Accordingly, the paper feeder in the present invention has the following advantages:

Firstly, as shown in FIG. 3B, the separation plate 46 has a cavity 462 on the back and a V-shaped slit 464 on the front. The cavity 462 is utilized for allocating the spherical node 472, and the V-shaped slit 464 is utilized for guiding the separation pad 45. The design of the separation plate 46 has the spherical node 472 pressing on the separation plate 46 effectively and has the separation pad 45 positioning on the separation roller 44 precisely to enable proper feeding alignment.

Secondly, as shown in FIG. 3A, the pressing device 47 in the present invention has the gap adjusting screw 477 and the force adjusting screw 478. The gap adjusting screw 477 is utilized for adjusting the size of the gap between the separation pad 45 and the separation roller 44. After the size of the gap is decided, the force adjusting screw 478 is utilized for further adjusting the compression of the elastic unit 476 to decide the force the separation pad 45 pressing on the separation roller 44. Thereby, for papers with different thickness and characteristics, the gap between the separation pad 45 and the separation roller 44 as well as the force applied by the separation roller 44 to the sheet of paper may be adjusted to prevent the problem of multiple feed.

While the preferred embodiments of the present invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the present invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the present invention. 

1. A paper feeder comprising: a pickup roller, for driving a sheet of paper; a separation roller, located downstream the pickup roller, having a shaft; a separation pad, having a curved separation portion leaning to the separation roller; a pressing device, having a spherical node; and a separation plate, having a cavity on a back thereof for allocating the spherical node, and a V-shaped slit on a front thereof for pressing the separation pad on the separation roller; wherein as the spherical node is pressed on the separation plate, the V-shaped slit is guided to be parallel to the shaft of the separation roller to have the curved separation portion leaning on the separation roller.
 2. The paper feeder of claim 1, wherein the pressing device further having an elastic unit for providing force to have the spherical node pressing on the separation plate.
 3. The paper feeder of claim 2, wherein the pressing device further having a basis and a gap adjusting screw, wherein the basis has an opening to have the spherical node protruding downward in contact with the separation plate, and the gap adjusting screw is screwed fixed to the basis and touches a rear end of the spherical node for adjusting a gap between the separation pad and the separation roller.
 4. The paper feeder of claim 3, wherein the pressing device further having a force adjusting screw screwed fixed to the gap adjusting screw and pushed against the elastic unit for adjusting the force provided by the elastic unit.
 5. The paper feeder of claim 3, wherein the separation plate is movably assembled to the basis of the pressing device and is fixed on the basis by the gap adjusting screw.
 6. The paper feeder of claim 5, wherein the separation pad is movably assembled to the separation plate.
 7. The paper feeder of claim 1, wherein the cavity has a curved surface with a curvature smaller than that of the spherical node.
 8. The paper feeder of claim 1, wherein the cavity has a spherical surface.
 9. The paper feeder of claim 1, further comprising a calibration pad utilized for interposing into the gap between the separation pad and the separation roller for adjusting the size of the gap.
 10. The paper feeder of claim 9, wherein the calibration pad has a thickness ranged between one sheet of paper and two sheets of paper.
 11. An automatic document feeder (ADF) comprising: a paper tray, for placing at least a sheet of paper; a paper feeder having: a pickup roller, for driving the sheet of paper; a separation roller, located downstream the pickup roller, having a shaft; a separation pad, having a curved separation portion leaning to the separation roller; a pressing device, having a spherical node; and a separation plate, having a cavity on a back thereof for allocating the spherical node, and a V-shaped slit on a front thereof for pressing the separation pad on the separation roller; wherein as the spherical node is pressed on the separation plate, the V-shaped slit is guided to be parallel to a shaft of the separation roller to have the curved separation portion leaning on the separation roller; a midway roller set, located downstream the paper feeder, for taking the sheet of paper away from the paper feeder to a scanning or printing position; and an exit roller set, located downstream the midway roller set, for taking the sheet of paper away from the scanning or printing position and for outputting the sheet of paper.
 12. The ADF of claim 11, wherein the pressing device further having an elastic unit for providing force to have the spherical node pressing on the separation plate.
 13. The ADF of claim 12, wherein the pressing device further having a basis and a gap adjusting screw, wherein the basis has an opening to have the spherical node protruding downward in contact with the separation plate, and the gap adjusting screw is screwed fixed to the basis and touches a rear end of the spherical node for adjusting a gap between the separation pad and the separation roller.
 14. The ADF of claim 13, wherein the pressing device further having a force adjusting screw screwed fixed to the gap adjusting screw and pushed against the elastic unit for adjusting the force provided by the elastic unit.
 15. The ADF of claim 13, wherein the separation plate is movably assembled to the basis of the pressing device and is fixed on the basis by the gap adjusting screw.
 16. The ADF of claim 15, wherein the separation pad is movably assembled to the separation plate.
 17. The ADF of claim 11, wherein the cavity has a curved surface with a curvature smaller than that of the spherical node.
 18. The ADF of claim 11, wherein the cavity a spherical surface.
 19. The ADF of claim 11, further comprising a calibration pad utilized for interposing into the gap between the separation pad and the separation roller for adjusting the size of the gap.
 20. The ADF of claim 19, wherein the calibration pad has a thickness ranged between one sheet of paper and two sheets of paper. 